Vaccine Aims to Block Bladder Infections
Animal Studies Could Lead to Nasal Spray That Protects Against Urinary Tract Infections
Sept. 17, 2009 -- For millions of women and some men, bladder infections are
a painful part of life.
More than half of women will have at least one urinary tract infection in
their lifetime and many will have recurrent infections. Men get them too, but
much less often than women and usually as a result of another medical problem,
such as kidney stones or an enlarged prostate.
Although easily treated in most cases, the infections are not so easily
prevented. But early animal research might lead to a nasal spray that protects
against bladder and other urinary tract infections.
Researchers from the University of Michigan created the nasal vaccine, which
targets specific strains of the Escherichia coli (E. coli) bacterium
that causes most urinary tract infections.
Mouse Studies Promising
In animal studies, mice treated with three of six experimental vaccine
candidates tested by the researchers developed antibodies against the bacteria
and became resistant to infection.
The mice received an initial immunization, delivered via nasal spray,
followed by two booster sprays a few weeks later, lead researcher Harry L.T.
Mobley, PhD, tells WebMD.
“We screened more than 5,300 possible proteins and ended up with three that
were very effective for preventing infection,” Mobley says.
In a separate study, the researchers looked for, and found, these proteins
in E. coli strains obtained from women treated for urinary tract
“This suggests we are on the right track and that this might prove to be an
effective vaccine in humans,” he says.
The researchers hope to test the vaccine in humans but have no firm plans to
do so. Mobley says a commercially available vaccine based on the research is at
best years away.
245,000 UTI Hospitalizations Each Year
The University of Michigan researchers are not the first to attempt a
vaccine to prevent urinary tract infections, and urologist Tomas Griebling, MD,
MPH, tells WebMD that such a vaccine makes a lot of sense.
Griebling is vice chairman of the department of urology at the University of
Kansas Medical Center.
By one estimate, urinary tract infections account for 6.8 million visits to
doctors, 1.3 million emergency room trips, and 245,000 hospitalizations a year
in the United States at a cost of $2.4 billion.
“The costs associated with urinary tract infections far exceed that of any
other urologic disorder,” he says.
Although in most cases the infections are not serious, when bacteria move
beyond the bladder into the kidney or the blood or when infections involve
antibiotic-resistant bacteria, they can become deadly.
The death of a Brazilian model early this year was a reminder of this
Doctors reportedly misdiagnosed 20-year-old Mariana Bridi’s urinary tract
infection, which was caused not by E. coli but by another bacterium,
called Pseudomonas aeruginosa.
Widespread infection led doctors to amputate Bridi’s hands and feet in an
effort to save her life, but the model died within weeks of entering the
A vaccine targeting the E. coli infection that causes most urinary
tract infections would not have saved Bridi, but it could keep millions of
people from becoming infected each year and save the health care system
billions of dollars a year, Griebling says.
“This is an ideal infection to try and target with a vaccine because it is
so common,” he says. “I would say the early research looks promising, even
though this certainly isn’t ready for prime time. But if they could produce a
nasal vaccine that is safe and cost-effective it could have a dramatic